Maths CE 91 measuration

91--44)


圖片參考：http://imgcld.yimg.com/8/n/HA04628698/o/20131223231227.jpg

Let n circles can be cut at most :
1 + (n-1)√((1+1)² - 1²) + 1 ≤ 40
(n-1)√3 ≤ 38
n ≤ 38/√3 + 1 = 22.939...
n at most 22 , choose (C).


91--53)

△AMB = △AMC and △KMB = △KMC
∴
△AMB - △KMB =△AMC - △KMC
△AKB = △AKC
;
△ADK / △AKC
= (△AKB - △DKB) / △AKC
= (△AKB - △AKB × DB/(AD+DB)) / △AKC
= (△AKB - △AKB × 1/(2+1)) / △AKC
= △AKB × 2/3 / △AKC
= 2/3
Choose (B).

2014-01-05 19:09:21 補充：
Thankyou! Happy New Year!

Happy New Year! 2014